Acoustic micro imaging device having at least one balanced linear motor assembly

Abstract

A scanning acoustic microscope including an ultrasonic transducer and a balanced linear motor assembly is disclosed. The balanced linear motor assembly includes a counterweight that is mounted for movement along a linear path that is parallel to the first linear path on which the transducer travels. The counterweight has a mass that is generally equal to the mass of the rotor and the transducer. The counterweight is being adapted to be moved, when the scanning acoustic microscope is used to interrogate a sample, along the second linear path at the same time that the rotor and transducer are being moved along the first linear path to allow the transducer to accelerate and decelerate without creating vibration.

1. A scanning acoustic microscope, comprising:
 a balanced brushless linear motor assembly including a stator and a rotor, wherein application of electric current to the rotor causes the rotor to move along a linear path defined by the stator; 
 wherein the stator includes at least one permanent magnetic member as a part thereof and the rotor includes at least one winding as a part thereof; 
 an ultrasonic transducer that is designed to emit pulses of acoustic energy through a coupling medium and that is directly driven by the rotor; 
 a controller that is designed to
 (a) cause control currents to be applied to the at least one winding of the rotor, the flow of the control currents through the at least one winding generating a magnetic field that interacts with a magnetic field emitted from the at least one permanent magnetic member to thereby cause the rotor and ultrasonic transducer to move along the linear path, and 
 (b) cause the ultrasonic transducer to emit pulses of ultrasonic energy at a target at predetermined times to at least partially interrogate a target; 
 
 a counterweight that is mounted for movement along a second linear path that is generally parallel to the linear path, the counterweight having generally the same mass as a mass of the ultrasonic transducer and the rotor; and 
 wherein the scanning acoustic microscope is designed so that, whenever the controller causes the rotor and ultrasonic transducer to move in a given direction along the first linear path, the counterweight is moved in the opposite direction along the second linear path thereby allowing the rotor and ultrasonic transducer to be subject to at least five G of force when accelerated or decelerated while maintaining the viability of data that is generated when the target is interrogated. 
 
   
   
     2. The scanning acoustic microscope of  claim 1 , wherein the transducer follows one or more non-linear traces when the target is being interrogated. 
   
   
     3. The scanning acoustic microscope of  claim 1 , wherein the transducer is operatively coupled to the target via a coupling medium when the target is being interrogated, the controller being adapted to cause the ultrasonic transducer to emit a pulse of acoustic energy toward each one of a plurality of three-dimensionally varied points located within a given volume defined inside of the target, the ultrasonic transducer having, for each one of the pulses, a focal point that is disposed at the same location within the given volume of the target as the corresponding one of the three dimensionally varied points. 
   
   
     4. The scanning acoustic microscope of  claim 1 , wherein the transducer is operatively coupled to the target via a coupling medium when the target is being interrogated, the controller being adapted to cause the ultrasonic transducer to emit a pulse of acoustic energy toward each one of a plurality of three-dimensionally varied points located within a given volume defined inside of the target, the transducer having, for each one of the pulses, a focal point that is disposed at the same location within the given volume of the target as the corresponding one of the three dimensionally varied points, the controller being further adapted to cause the transducer to receive a reflection signal corresponding to each one of the pulses, each one of the reflection signals comprising an A-Scan of the target that is in-focus at the point within the given volume of the target corresponding thereto, all of the reflection signals representing acoustic impedance features present within the given volume defined inside of the target. 
   
   
     5. The scanning acoustic microscope of  claim 1 , further comprising a second linear motor assembly for moving at least the transducer in a direction that is perpendicular to the linear axis. 
   
   
     6. The scanning acoustic microscope of  claim 1 , further comprising a second balanced motor assembly for moving at least the transducer in a direction that is perpendicular to the linear axis. 
   
   
     7. The scanning acoustic microscope of  claim 1 , wherein the first linear path is co-linear with the second linear path. 
   
   
     8. The scanning acoustic microscope of  claim 1 , wherein the counterweight comprises a second ultrasonic transducer. 
   
   
     9. The scanning acoustic microscope of  claim 1 , wherein the target comprises a microelectronic target. 
   
   
     10. The scanning acoustic microscope of  claim 1 , further comprising a belt and pulley assembly that connects the counterweight to the transducer and rotor. 
   
   
     11. The scanning acoustic microscope of  claim 1 , wherein controller is adapted to cause the transducer to be moved in an X-Y raster scan with respect to the target. 
   
   
     12. The scanning acoustic microscope of  claim 1 , wherein the first and second linear paths are spaced apart from each other, the center of the mass of the counterweight being located to reduce at least some of the rotational forces that are generated when the transducer is slowed down and changes direction. 
   
   
     13. The scanning acoustic microscope of  claim 1 , wherein the target comprises a sealed package. 
   
   
     14. The scanning acoustic microscope of  claim 1 , wherein the target comprises a biological material. 
   
   
     15. A scanning acoustic microscope, comprising:
 first and second balanced brushless linear motor assemblies including first and second stators and first and second rotors, respectively, wherein application of current to the first and second rotors causes the first and second rotors to move along first and second linear paths defined by the first and second stators, respectively; 
 wherein the first and second stators include at least one permanent magnetic member as a part thereof and the first and second rotors include at least one winding as a part thereof; 
 first and second ultrasonic transducers that are directly driven by the first and second rotors, respectively, and that are designed to emit pulses of acoustic energy through a coupling medium; 
 a controller that is designed to
 (a) cause control currents to be applied to the at least one winding of the first and second rotors, the flow of the control currents through the at least one windings of the first and second rotors generating first and second magnetic fields that interact with first and second magnetic fields emitted from the at least one permanent magnetic members of the first and second stators, respectively, to thereby cause the first and second rotors and the first and second ultrasonic transducers to move along the first and second linear paths, respectively, and 
 (b) cause the first and second ultrasonic transducers to emit pulses of ultrasonic energy at the target at predetermined times to at least partially interrogate first and second targets; 
 
 wherein the first and second linear paths are generally parallel to each other and a mass of the first ultrasonic transducer and the first rotor is generally equal to a mass of the second ultrasonic transducer and the second rotor; and 
 wherein the scanning acoustic microscope is designed so that, whenever the controller causes the first rotor and first ultrasonic transducer to move in a given direction along the first linear path, the controller causes the second ultrasonic transducer and the second rotor to be moved in the opposite direction along the second linear path thereby allowing the first and second rotors and the first and second ultrasonic transducers to be subject to at least five G of force when accelerated or decelerated while maintaining the viability of data that is generated when the first and second targets are interrogated. 
 
   
   
     16. The scanning acoustic microscope of  claim 15 , wherein the controller is adapted to cause the first and second ultrasonic transducers to emit a pulse of acoustic energy toward each one of a plurality of three-dimensionally varied points located within a given volume defined inside of the first and second targets, respectively, the first and second ultrasonic transducers having, for each one of the pulses, a focal point that is disposed at the same location within the given volume of the first and second targets as the corresponding one of the three dimensionally varied points. 
   
   
     17. The scanning acoustic microscope of  claim 15 , wherein the controller is adapted to cause the first and second ultrasonic transducers to emit a pulse of acoustic energy toward each one of a plurality of three-dimensionally varied points located within a given volume defined inside of the first and second targets, respectively, the first and second transducers having, for each one of the pulses, a focal point that is disposed at the same location within the given volume of the target as the corresponding one of the three dimensionally varied points inside the first and second targets, respectively, the controller being further adapted to cause the first and second transducers to receive a reflection signal corresponding to each one of the pulses, each one of the reflection signals comprising an A-Scan of the target that is in-focus at the point within the given volume of the first and second targets corresponding thereto, all of the reflection signals representing acoustic impedance features present within the given volume defined inside of the first and second targets. 
   
   
     18. The scanning acoustic microscope of  claim 15 , wherein the first linear path is co-linear with the second linear path. 
   
   
     19. The scanning acoustic microscope of  claim 15 , wherein one of the first and second targets comprises a microelectronic target. 
   
   
     20. The scanning acoustic microscope of  claim 15 , wherein controller is adapted to cause one of the first ultrasonic transducers to be moved in an X-Y raster scan with respect to the first or second target corresponding thereto. 
   
   
     21. The scanning acoustic microscope of  claim 15 , wherein one of the first and second targets comprises a sealed package. 
   
   
     22. The scanning acoustic microscope of  claim 15 , wherein one of the first and second targets comprises a biological material.